In casting production processes, castings need to be frequently handled, postures of castings need to be adjusted, and various cleaning operations to castings need to be completed. During production, mold cores and core iron need to be removed, excess metals such as gates, risers, added parts, tie bars, cut bars, flashes and burrs need to be cut off, burnt-on sand and surface foreign matters on castings need to be removed, and casting surfaces need to be ground flat. Up to now, operations to most castings are performed still mainly by means of manual tools and semi-mechanical tools such as pneumatic rammers, pneumatic shovels, high-speed handheld grinding wheels, and suspended grinding wheels. For castings with less complex appearances, universal punching machines and sawing machines are adopted. When castings are produced in a large batch, special machines or special production lines are adopted to realize automatic operations. Steel castings are mostly cut by means of oxygen cutting or gas-electric cutting. Gas-electric cutting refers to a process of using high temperature produced by arc formed between an electrode and a casting to melt or oxidize metals, and simultaneously using a high-pressure and high-speed gas flow to purge molten substances to remove flashes, burrs, and protrusions on castings. This method not only is used for cutting casting heads, but also can be used for flattening casting surfaces. However, gas-electric cutting has the disadvantage that arc light, smoke, and noise are produced.
Burrs, inner gates, and casting head residues on parting surfaces of castings are structures which inevitably exist on castings, all the more so for special-shaped castings, and cleaning and grinding treatment is required. In the past, casting cleaning fully relies on manual operations, the working efficiency is extremely low, the working environment is severe, the labor cost is high, and the labor intensity is great. In a manual casting cleaning process, there are many positions which need to be cleaned for special-shaped castings, the structure is thick and large, the cleaning is quite difficult, and the working efficiency is low; and it is not easy to perform control during manual cleaning, frequently causing the casting quality to be instable; the structure of special-shaped castings is complex, there are many positions which need to be cleaned, workers need to handle the castings endlessly to change angles such that cleaning can be realized; fine dust produced during cleaning is scattered throughout workshops, and consequently the physical health of workers is seriously influenced; and more importantly, the safety of workers cannot be guaranteed.
Handling and posture adjustment of castings are generally performed through manual operations or under the assistance of simple mechanical devices, the degree of human participation is high, the man-hour is greatly consumed, the manufacturing cost is increased, and the manufacturing progress is delayed. Therefore, there is an urgent need to design an automatic device which can simultaneously satisfy the demands of handling, posture adjustment and cleaning operations of castings, and especially satisfy the demands of cleaning operations of heavy-weight, large-size and complex castings, so as to improve the working efficiency of casting cleaning operations and guarantee the quality of casting products.
Aiming at the problems existing in handling and cleaning of castings, current patent literatures also provide some solutions. Chinese patent application No. 200810137471.1 discloses a suspended type pipe-jointing welding robot, which consists of an electrical sliding loop part, a swinging mechanism, a telescoping mechanism, and a manually lifting adjustment mechanism, and realizes automatic welding of differently shaped joint pipes through a rotating mechanism and a telescoping mechanism. However, this technical solution can only realize single-arm type operations and cannot realize multi-arm joint operations. Chinese patent application No. 200710176284 discloses a crawler type multi-arm rod mobile robot, which consists of an arm working device and a crawler walking device, can replace humans to work on various complex pavements. However, the stability is poor when workpieces are grasped, and the operation demands of complex castings cannot be satisfied. Chinese patent application No. 201410438219.X discloses a robot capable of multi-arm handling, which consists of parts such as guide rails and a plurality of individually driven arms, and can simultaneously load and lift cargoes (such as substrates or wafers) which are loaded up and down according to a given pitch unit. However, a single arm is adopted to work alone during handling, and only simple translation and grasping can be performed. Chinese patent application No. 201710121995.3 discloses a suspended type car seat stereoscopic welding robot, wherein a single-arm robot body is suspended on an outer annular rail and an inner annular rail through an outer pulley and an inner pulley and can move and travel along the outer annular rail and the inner annular rail. This solution adopts a two-point suspension fixing manner, which is poor in stability. Chinese patent application No. 201620856209.2 discloses an automatic casting cleaning device, which comprises a robot, a tool magazine, cutters, a rotary worktable, and a controller, and uses a cutter grasped by a power head to clean a casting to be cleaned, wherein the rotary worktable is rotatable such that the casting to be cleaned is located within the cleaning range of the robot. Chinese patent application No. 201510512610.4 discloses a compact type robot automated grinding device, which uses a robot to grasp a casting and move it to a grinding device for grinding. This type of automated grinding device has the following disadvantages: 1) the loading capacity of the robot is limited, and the robot cannot bear too heavy castings; and 2) the feeding movement in the grinding process is the movement of castings, which is not suitable for large-size castings. Chinese patent application No. 201610072103.8 discloses a casting cleaning unit and method, which adopt two robots fixed at different working positions on the ground to grasp a casting to perform cleaning operations such as grinding. However, the working efficiency is low, and the working spaces of the robots are small. With the improvement of casting technical level, the demands of production of large castings, handling, posture adjustment, and cleaning automation of castings are increasingly great. In the existing technical solutions, single-arm robots are mostly adopted to work alone or in combination, and the demands of handling, posture adjustment, and cleaning operations of heavy-weight, large-size, and complex special-shaped castings cannot be satisfied.